A small pilot study by Alberts and team (Cleveland Clinic) suggests that sustained forced exercise (FE) may be as or more effective than medication or surgical implantation of microelectrodes for deep brain stimulation in improving motor function in individuals with Parkinson's disease (PD). In FE, an individual actively exercises at a rate in excess of that which (s)he is physically able to attain and maintain by (her)himself. In the Alberts'study, patients completed three 40 min FE sessions/week for 8 weeks, using a stationary tandem bicycle on which a "trainer" provided ~75% of the energy required to maintain a cadence of 80-90 rpm and the patient provided sufficient energy to maintain a target heart rate 80% of maximum for their age. Somewhat surprisingly, this regimen improved upper as well as lower body motor function. Unfortunately, commercialization of this FE regimen would be prohibitively expensive, requiring a healthy trainer to man the front seat of the stationary tandem and a supervisor to insure the targeted level of FE was reached and maintained. RSS Industries, Inc. proposes to design, build and bench test the performance of a motorized exercise cycle prototype, the Theracycle PD, able to replace the physical input provided by the trainer in the Alberts'FE regimen. The starting point will be the existing Theracycle, a stationary, software-controlled motor driven therapeutic exercise system developed and manufactured by RSS and launched in 2002 for use by individuals with significant physical disabilities. Innovations and enhancements to be implemented during the 1 year SBIR Phase I work plan will enable the prototype Theracycle PD to: 1) allow the rider to achieve FE by overdriving the motor;and 2) use the rider's heart rate as part of a control loop to signal when more pedaling effort is required to maintain target heart rate (and FE) and when the motor can provide the effort. Specific aims (SAs) include: SA1. Replace existing gear box on a standard Theracycle with a back-drivable, low resistance gearing system. SA 2: Develop and integrate a heart rate monitor, electronic components, enhanced GUI and requisite soft- ware. SA 3: Build and release test 3 additional prototype Theracycle PD units for use in clinical efficacy testing of FE regimens in SBIR Phase II (4 units total;1 primary and 1 backup for each of 2 clinical sites). Feasibility/Progression Criteria: The heart rate and pedal cadence values achieved during the FE period on the Theracycle PD prototypes must be within 10% of the range of values reported in the Alberts'pilot study. No attempt will be made to ascertain effectiveness of the FE regimen as that will be addressed in SBIR Phase II. PUBLIC HEALTH RELEVANCE: Individuals with Parkinson's disease (PD) suffer progressive loss of upper and lower body motor functions, for which drug therapy becomes less and less effective over time. A recent pilot study suggests that forced exercise on a tandem bicycle (in which a second rider aids in pedaling at a rate well above that achievable by a PD patient's voluntary effort) can produce whole body improvements in motor function at least as good as and possibly better than those achieved by medication in patients with advanced disease. The work proposed here is designed to create the Theracycle PD, a stationary exercise cycle using a motor to replace the physical effort provided by the second rider, with the long term goal of making forced exercise an affordable (<$5000) option available to a much wider group of PD patients.